1. Field of Invention
The present invention relates to novel semi-synthetic peptide antibiotics, to processes of their production, and to their use as agents for inhibiting mammalian neoplasms.
2. Description of the Prior Art
Disclosed in our co-pending application U.S. Ser. No. 855,649, filed Apr. 25, 1986, now U.S. Pat. No. 4,692,510, are peptide antibiotics BU-2867T A, B, and C having the formula I wherein E represents the trans configuration of the double bond ##STR1## BU-2867T, A, B, and C are produced by fermentation using the novel microorganisms Polyangium brachysporum strain K481-B101 (deposited with the ATCC and assigned the culture No. 53,080); they are useful as antitumor and antifungal agents.
The BU-2867T antibiotics yield useful synthetic intermediates when subjected to enzymatic cleavage. For example, when BU-2867T A was treated with the enzyme papain, a compound having the formula II (hereinafter referred to as "Compound II") ##STR2## was obtained. Treatment of BU-2867T A with Pseudomonas acylase yielded a compound having the formula III (hereinafter referred to as "Compound III"). ##STR3##
The present invention takes advantage of the synthetic utility of intermediate compounds II and III to provide novel antitunor semi-synthetic derivatives of antibiotics BU-2867T A, B, and C.